wont run over half throttle

[martin47]

on the water over around half throttle my 115hp straight 6 mercury bogs down she runs perfect up till then
starts great and don't miss a beat iv checked fuel pips air vent on tanks cleaned the carbs iv tried pumping the primer pump while running and no different iv had it in the shop and they don't know the problem is the fault is only there afloat
under load any I dears ?? I was going to get new carb kits and try that ??

 

[alldodge]

Re: wont run over half throttle

on the water over around half throttle my 115hp straight 6 mercury bogs down she runs perfect up till then
starts great and don't miss a beat iv checked fuel pips air vent on tanks cleaned the carbs iv tried pumping the primer pump while running and no different iv had it in the shop and they don't know the problem is the fault is only there afloat
under load any I dears ?? I was going to get new carb kits and try that ??

Check the fuel line from start to finish and see if it is getting pinched. If good suggest checking compression

 

[CharlieB]

Re: wont run over half throttle

First thing is check fuel flow to the carbs. PUll the fuel hose just after the fuel pump, crank the motor, you don't need to start it. You just want to see that there is a strong pulsed fuel flow. If that checks good then pull the carbs as one or more may have either a dirty main jet not flowing enough fuel OR the carbs may still have the screens on the fuel hose inlet fitting. Clean or remove those screens. Reduced fuel flow on one carbs will cause two cyls to run lean, raising combustion temps too high and begin melting pistons.